refactor: rename custom components from shannon-* to hightower-*

Renames API server, worker jobs, credentials secret, and workspaces
PVC to use the hightower prefix. Upstream Shannon names (namespace,
Temporal service, package imports, .shannon/ dir) are unchanged.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/infra/base/rbac.yaml

@@ -1,7 +1,7 @@
 apiVersion: rbac.authorization.k8s.io/v1
 kind: Role
 metadata:
-  name: shannon-api
+  name: hightower-api
   namespace: shannon
 rules:
   - apiGroups: ["batch"]
@@ -17,13 +17,13 @@ rules:
 apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding
 metadata:
-  name: shannon-api
+  name: hightower-api
   namespace: shannon
 subjects:
   - kind: ServiceAccount
-    name: shannon-api
+    name: hightower-api
     namespace: shannon
 roleRef:
   kind: Role
-  name: shannon-api
+  name: hightower-api
   apiGroup: rbac.authorization.k8s.io